CORRECTS DATE - In this photo taken on Wednesday afternoon, March 16, 2011 and released on Thursday, March 17 by Tokyo Electric Power Co. (TEPCO), thick white smoke billows from the No. 3 unit of the Fukushima Dai-ichi nuclear power plant in Okumamachi, Fukushima Prefecture. A nearly completed new power line could restore cooling systems in Japan's tsunami-crippled nuclear power plant, its operator said Thursday, raising some hope of easing the crisis that has threatened a meltdown and already spawned dangerous radiation surges. (AP Photo/Tokyo Electric Power Co.) EDITORIAL USE ONLY, NO SALES

Winds passing over Japan's stricken nuclear power plant are reaching California and moving inland, but health experts say the plumes pose no danger to the public.

There is mounting alarm in the public's mind as news continues of explosions and loss of reactor cooling water at the Fukushima Dai-ichi plant, and its intensely radioactive fuel rods.

But winds from Japan have been blowing eastward across the Pacific at altitudes four to five miles high, and are "continually mixing with the upper atmosphere," said Kenneth Bowman, a noted atmospheric physicist at Texas A&M University and an expert on computer-based modeling of wind behavior.

Particles significantly diluted

Bowman cautioned in an interview that he is not an expert in studying what the winds may hold - including radioactive particles - but he noted that at their high altitudes anything they carry is likely to be significantly diluted.

Bowman has created daily maps forecasting the winds blowing across the Pacific from the reactor site in Japan and said Thursday they had reached the coast of Alaska and the Pacific Northwest and were trending southeast to California.

He bases his forecast calculation maps on hourly reports from the National Oceanic and Atmospheric Center's wind tracking center, and cautioned: "My calculations are only as good as the winds are."

State public health officials said they have been getting hundreds of calls every day from people concerned about radiation reaching California. In a conference call with reporters Thursday, officials repeatedly stressed that there is no health threat in California from radiation that may come from Japan.

"There is no reason to be nervous. There is no reason to have concern," said Mike Dayton, acting secretary of California's Emergency Management Agency. "Even in the worst-case scenario (in Japan), there is no threat to public health in California."

The state has eight stations constantly monitoring radiation levels, public health officials said. So far, none of them has detected any increases in radiation.

Public health experts also noted that no one should be taking or hoarding potassium iodide, a form of salt that can protect people against developing thyroid cancer when they're exposed to radioactive iodine. Pharmacies across the state have reported strong sales of the pills in recent days, and some have run out altogether.

No one in California will be exposed to enough radiation to warrant taking the pills, public health officials said, and some people can suffer serious side effects from potassium iodide, including allergic reactions, nausea and skin rashes.

"The biggest health impact (from this radiation) is the psychological impact. It leads people to want to do whatever they can," said Dr. Jonathan Fielding, director of public health in Los Angeles County. "We want to emphasize emergency preparedness, instead of worrying about the fact that their local drug store ran out of potassium iodide."

In a statement in Washington on Thursday, President Obama had reassuring words after a briefing from experts at several federal agencies:

"We do not expect harmful levels of radiation to reach the United States, whether it's the West Coast, Hawaii, Alaska or U.S. territories in the Pacific," he said. "That is the judgment of our Nuclear Regulatory Commission and many other experts.